I had terrible heartburn too, and my doctor put me on a 20mg Pepcid (after Zantac did nothing!)...I only try to take it when I need it and not everyday.
You can also take Maalox or Mylanta. Tastes horrible, but helps a lot. Milk can also help coat your esophagus. I hope you feel better soon :) I know this part stinks....
Oh girl:-) I feel your pain. I had heartburn from the day I found out I was pregnant up until the moment he came out of me. ( I know this because Jello used to give me heartburn and b/c i was a scheduled c-section, i didn't eat anything until he was born and that's what they gave me Jello...) The only thing that worked was the tums, you can increase the amount you are consuming to the max on the back of the bottle but only take them when you get the heartburn. If you get it only when you eat (that's when I got it. It didn't matter what I ate, I got heartburn), divide the tums and take a few minutes before you eat. Other than that, you have to just grin and bear it:-)
I always used Zantac 150 with great results. Tums and stuff never worked for me. I hope it gets better soon!